1. Field of the Invention
The present invention relates to an electrorheological fluid-applied apparatus in which the characteristics of an electrorheological fluid are utilized very efficiently, and also relates to an electrorheological fluid-applied vibration controller and an electrorheological fluid-applied fixing apparatus which are included among the types of electrorheological fluid-applied apparatus.
2. Description of the Related Art
As applied apparatuses making use of an electrorheological fluid, or an electroviscous fluid, whose viscosity changes upon application of a voltage thereto, a vibration isolating apparatus is disclosed in Japanese Patent Application Laid-Open No. 63-72934, and a suspension is disclosed in Japanese Patent Application Laid-Open No. 63-265715. In these applied apparatuses, the viscosity of a fluid in an electrode orifice is changed by applying a voltage to the orifice provided in a hermetically sealed fluid chamber, so as to control the mechanical properties of the apparatus concerned. In addition, Japanese Patent Application Laid-Open Nos. 62-113935 and 62-113936 disclose spring elements. Furthermore, Japanese Patent Application Laid-Open No. 61-2966 discloses an electrorheological fluid clutch in which an input shaft is coupled with an output shaft via an electrorheological fluid and which is capable of changing the torque transmission efficiency upon application of a voltage to the electrorheological fluid. Also, Japanese Patent Application Laid-Open No. 1-119377 discloses a vibrating apparatus using an electroviscous valve.
In each of the conventional apparatuses typified by the aforementioned apparatuses, control is effected by making use of a phenomenon in which the viscosity of an electrorheological fluid changes in response to a change in the applied voltage, i.e., a phenomenon in which a shearing stress appearing in an electrode portion changes in response to a change in the applied voltage.
At the present stage, it is difficult to say that the change in the shearing stress in response to the applied voltage has reached a level required of the aforementioned applied apparatuses. For this reason, the application of the electrorheological fluid is quite limited. In addition, since the change in the shearing stress of the electrorheological fluid occurring between electrodes is very small in an area where deformation in the shearing direction is very small, it has been difficult to apply the electrorheological fluid to control very small vibrations.